1. Field of the Invention
The invention relates to a switch apparatus, particularly to a hybrid optical switch apparatus used for optical communication network equipment.
2. Description of the Prior Art
During the past decade, the demand of the optical switching system with high stability and high capacity is greatly increased due to the flourishing development of optical communication networks. The optical cross-connect (OXC) switches are the key components for the development of high-capacity and complex optical switching systems.
Recently, the optical switching systems are developed into all-optical switching to increase the bandwidths and transmission rates. Many different techniques, such as thermo-optics, liquid crystal, and microelectromechanical systems (MEMS), have been proposed for developing the all-optical switching devices. In the above-mentioned technological field, the MEMS technology has emerged to be the leading candidate. The MEMS-based component not only has high accuracy, but also has the advantages of miniaturization, batch production, and scalability.
Silicon mirrors fabricated by using MEMS technology are widely employed for the optical applications. Deep reactive ion etching (DRIE), surface micromachining and wet anisotropic etching are the most popular micromachining techniques to fabricate the silicon mirror. DRIE technique is usually used to create high-aspect-ratio structures and is not restricted by the crystal orientation of the silicon wafer. However, DRIE technique is relatively expensive. Surface micromachining is a versatile technique to realize various opto-mechanical components. But, surface micromachining requires more fabrication steps.
In addition, wet anisotropic etching which can reduce the manufacturing cost is more suitable for fabricating silicon micro-mirror. The wet anisotropic etching technique usually can be used to fabricate vertical and smooth (111) silicon micro-mirror with a (110) silicon wafer. However, the etched shapes are strongly restricted by the crystal orientation of the silicon wafer. For example, vertical (111) mirrors and V-grooves cannot be simultaneously fabricated on a (110) silicon wafer.
Thus, in order to eliminate the drawbacks of the prior arts, it is necessary to develop a novel optical switch, which possesses the advantages of high precision, high fabrication yield, low actuation voltage, low power consumption, low cost, and easy fiber alignment.